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Prosthodontic aspects of an implant for hemimandible
PROSTHODONTIC
ASPECTS OF AN IMPLANT
RALPH W. FLINCHBAUGH, LIEUTENANT COLONEL (DC),
FOR HEMIMANDIBLE USA
Fort Eustis, Vu.
P
ROSTHODONTISTS ARE FREQUENTLY CALLED uponto fabricate appliances for use in oral surgical problems. During the treatment of a young white male soldier, resection of the left-half of the mandible for recurrent ameloblastoma became necessary. The Prosthodontia Section of Fitzsimons Army Hospital was called in consultation. In an attempt to alleviate the well-known deformities which follow mandibular hemisection, it was decided to fabricate an implant to replace the structure to be lost, working entirely from preoperative measurements and calculations. The preliminary success of the operation was so complete that the technical details of the implant fabrication are felt worthy of reporting. At the latest report, the implant had functioned successfully for fifteen months. If continued success of the implant warrants the reporting of the oral surgical aspects of the case, prosthodontists may well be called upon for their talents for implant fabrication. TECHNIQUE
Surgical Vitallium was the material chosen for the implant because of the need for strength and for a material of proved tissue tolerance. The first problem concerned the form to be given the implant. In consultation with the surgeon, it was decided to form the implant to permit the attachment of the masticatory muscles. If this was possible, it was felt that function could be preserved and the mandibular sideshift following hemisection could be prevented. Another consideration was the necessity to support the facial tissues and maintain facial contour. It was also thought that if the condylar element was given a shape approximating normal anatomy that less physiologic remolding of the glenoid fossa would be required than if an arbitrary ball-shape was used. The second problem was one of measurements. To fabricate an implant preoperatively, accurate and adequate meas”nements were mandatory. To form the medial aspect of the implant to permit anchorage, it was necessary to determine the buccolingual widths of the mandible at all levels from the mesial side of the first premolar to the distal side of the second premolar, the site of the resection. Direct bone measurements were made by the Oral Surgical Section using local anesthesia. A draftsman’s compass with needle points was used intraorally and extraorally. Considerable difficulty was encountered with the compass points slipping off the inferior border of the mandihle. The angle at which the compass was held proved to he important in the measurements. The opinions or assertions contained herein are those of the author and are not to be construed a6 official or reflecting the views of the Army Department or the United States Army at large. Received for publication Nov. 20, 195’7. 1039
J. Pros. Den. Nov.-Dec., 195X
FLINCHBAUGH
1040
Large calipers and a face-bow were also used. Measurements of the width of the mandible were made extraorally in the region of the first premolars, the first molars, the angles, and the condyles. After making allowances for the tissues overlying the bone, a template was made from these measurements which represented an occlusal view of the patient’s mandible.
Fig. 1.-A
postoperative
roentgenogram
of the implant.
The most valuable measurements were made on a roentgenogram of the left side of the mandible. A six foot target-film distance was used for making the roentgenogram. Using tracing paper, a template was made from this life-sized view of the left side of the mandible. The roentgenogram showed the vertical thickness of the mandible at the site of the considered resection, the length of the mandible to the angle, the angulation of the angle, the distance from the angle to the superior aspect of the condyle, and the shape, form, and size of the ramus. After the measurements were completed, various dry skulls were examined. Fortunately, a skull with approximately the same measurements was available. Two elements of this skull’s mandible were reproduced as a starting point for fabrication of a wax pattern of the implant: the left condyle and the region of the second premolar. An alginate impression of the entire left condyle was made. Melted green sheet casting wax was poured into this mold to provide a wax cast of the condyle. This cast was thinned on all aspects except the anterior and superior gliding surfaces. Another alginate mold was made of the left side of the mandible of the skull from the angle to the midline. This mold was poured in plaster. The
ASPECTS
OF
AN
Fig. P.-The
IMPLANT
wax pattern
FOR
1041
HEMIMANDIRLE
of the implant.
Fig. 3.
Fig. 4.
Fig. 3.-The Fig. 4.-The
buccal view of the implant. lingual view of the implant.
1042
FLINCHBAUGH
J. Pros. Deu. Nov.-Dec., 1958
exact location of the proposed resection cut was marked on this cast and the cast was carefully sectioned. Then, using all of the preoperative measurements, the median portion was carved to what was thought to duplicate the patient’s mandible in the same region. This cast was used to mold the anterior portion of the implant wax pattern. The body of the implant wax pattern was formed of baseplate wax. The coronoid process was reproduced, but it was reduced materially in size as shown on the profile roentgenogram (Fig. 1) . Rounded edges on the wax pattern were provided by the use of half-round preformed wax strips. Fenestration was accomplished with a heated copper impression band. Both loops and holes were provided for attachment of the severed muscles (Fig. 2). However, after consultation with the surgeon, the loops were removed from the finished casting. It was thought the smoother the casting the less chance of tissue irritation. The screws to be used for attaching the implant were selected by the surgeon. The holes in the wax pattern were countersunk, using the same screws to be used at the time of the operation. The final step consisted of a meticulous recheck of all measurements and a polish of the wax pattern with oil of eucalyptus, the excess of which was removed with acetone. The wax pattern was cast commercially of surgical Vitallium (Figs. 3 and 4). On reflection postoperatively, one improvement in the pattern would have been beneficial ; the attaching flange on the inferior border of the mandible could have been extended to the midline. UNITED STATES ARMY FORT EUSTIS, VA.
DENTAL
DETACHMENT
ASPECTS OF AN IMPLANT
RALPH W. FLINCHBAUGH, LIEUTENANT COLONEL (DC),
FOR HEMIMANDIBLE USA
Fort Eustis, Vu.
P
ROSTHODONTISTS ARE FREQUENTLY CALLED uponto fabricate appliances for use in oral surgical problems. During the treatment of a young white male soldier, resection of the left-half of the mandible for recurrent ameloblastoma became necessary. The Prosthodontia Section of Fitzsimons Army Hospital was called in consultation. In an attempt to alleviate the well-known deformities which follow mandibular hemisection, it was decided to fabricate an implant to replace the structure to be lost, working entirely from preoperative measurements and calculations. The preliminary success of the operation was so complete that the technical details of the implant fabrication are felt worthy of reporting. At the latest report, the implant had functioned successfully for fifteen months. If continued success of the implant warrants the reporting of the oral surgical aspects of the case, prosthodontists may well be called upon for their talents for implant fabrication. TECHNIQUE
Surgical Vitallium was the material chosen for the implant because of the need for strength and for a material of proved tissue tolerance. The first problem concerned the form to be given the implant. In consultation with the surgeon, it was decided to form the implant to permit the attachment of the masticatory muscles. If this was possible, it was felt that function could be preserved and the mandibular sideshift following hemisection could be prevented. Another consideration was the necessity to support the facial tissues and maintain facial contour. It was also thought that if the condylar element was given a shape approximating normal anatomy that less physiologic remolding of the glenoid fossa would be required than if an arbitrary ball-shape was used. The second problem was one of measurements. To fabricate an implant preoperatively, accurate and adequate meas”nements were mandatory. To form the medial aspect of the implant to permit anchorage, it was necessary to determine the buccolingual widths of the mandible at all levels from the mesial side of the first premolar to the distal side of the second premolar, the site of the resection. Direct bone measurements were made by the Oral Surgical Section using local anesthesia. A draftsman’s compass with needle points was used intraorally and extraorally. Considerable difficulty was encountered with the compass points slipping off the inferior border of the mandihle. The angle at which the compass was held proved to he important in the measurements. The opinions or assertions contained herein are those of the author and are not to be construed a6 official or reflecting the views of the Army Department or the United States Army at large. Received for publication Nov. 20, 195’7. 1039
J. Pros. Den. Nov.-Dec., 195X
FLINCHBAUGH
1040
Large calipers and a face-bow were also used. Measurements of the width of the mandible were made extraorally in the region of the first premolars, the first molars, the angles, and the condyles. After making allowances for the tissues overlying the bone, a template was made from these measurements which represented an occlusal view of the patient’s mandible.
Fig. 1.-A
postoperative
roentgenogram
of the implant.
The most valuable measurements were made on a roentgenogram of the left side of the mandible. A six foot target-film distance was used for making the roentgenogram. Using tracing paper, a template was made from this life-sized view of the left side of the mandible. The roentgenogram showed the vertical thickness of the mandible at the site of the considered resection, the length of the mandible to the angle, the angulation of the angle, the distance from the angle to the superior aspect of the condyle, and the shape, form, and size of the ramus. After the measurements were completed, various dry skulls were examined. Fortunately, a skull with approximately the same measurements was available. Two elements of this skull’s mandible were reproduced as a starting point for fabrication of a wax pattern of the implant: the left condyle and the region of the second premolar. An alginate impression of the entire left condyle was made. Melted green sheet casting wax was poured into this mold to provide a wax cast of the condyle. This cast was thinned on all aspects except the anterior and superior gliding surfaces. Another alginate mold was made of the left side of the mandible of the skull from the angle to the midline. This mold was poured in plaster. The
ASPECTS
OF
AN
Fig. P.-The
IMPLANT
wax pattern
FOR
1041
HEMIMANDIRLE
of the implant.
Fig. 3.
Fig. 4.
Fig. 3.-The Fig. 4.-The
buccal view of the implant. lingual view of the implant.
1042
FLINCHBAUGH
J. Pros. Deu. Nov.-Dec., 1958
exact location of the proposed resection cut was marked on this cast and the cast was carefully sectioned. Then, using all of the preoperative measurements, the median portion was carved to what was thought to duplicate the patient’s mandible in the same region. This cast was used to mold the anterior portion of the implant wax pattern. The body of the implant wax pattern was formed of baseplate wax. The coronoid process was reproduced, but it was reduced materially in size as shown on the profile roentgenogram (Fig. 1) . Rounded edges on the wax pattern were provided by the use of half-round preformed wax strips. Fenestration was accomplished with a heated copper impression band. Both loops and holes were provided for attachment of the severed muscles (Fig. 2). However, after consultation with the surgeon, the loops were removed from the finished casting. It was thought the smoother the casting the less chance of tissue irritation. The screws to be used for attaching the implant were selected by the surgeon. The holes in the wax pattern were countersunk, using the same screws to be used at the time of the operation. The final step consisted of a meticulous recheck of all measurements and a polish of the wax pattern with oil of eucalyptus, the excess of which was removed with acetone. The wax pattern was cast commercially of surgical Vitallium (Figs. 3 and 4). On reflection postoperatively, one improvement in the pattern would have been beneficial ; the attaching flange on the inferior border of the mandible could have been extended to the midline. UNITED STATES ARMY FORT EUSTIS, VA.
DENTAL
DETACHMENT